1. Field of the Invention
The preset invention relates to a robot controller for controlling a robot, and in particular, relates to a robot controller having a function to specify a teaching operation of the robot by learning and improving motion performance of the robot.
2. Description of the Related Art
In a factory in which a system constituted by a robot and peripheral equipment is installed, a target cycle time in a production line including the system is determined. In order to achieve the target cycle time, a teaching operator carries out teaching operation by trial and error based on experience and know-how, for example, by modifying a teaching program and teaching the motion which is easily executed by the robot. In such a case, the improvement of the motion velocity of the robot depends on the skill of the operator, and the operation by the operator is inefficient and takes a long time.
In order to solve the above problem, for example, Japanese Unexamined Patent Publication (Kokai) No. 2011-167817 (JP 2011-167817 A) discloses a robot controller including an ordinary control part for controlling the motion of a robot mechanical unit; and a learning control part for operating the robot mechanical unit with a work program, and learning to calculate a learning correction value to approximate a controlled position of the robot mechanical unit detected by a sensor to a target trajectory or position given to the ordinary control part. In this case, the learning control part calculates the maximum velocity override which can be set in a learning operation condition, and calculates the learning correction value while increasing the velocity override by a plurality of times until it reaches the maximum velocity override.
In JP 2011-167817 A, by repeatedly learning the same motion, the motion velocity of the robot can be increased without depending on the skill of an operator. However, in JP 2011-167817 A, it is necessary to provide an additional sensor to the robot, in order to restrain vibration of the robot with high accuracy. Further, when the position and orientation of the robot are sequentially changed due to the condition of a workpiece, etc., it may be difficult to repeatedly learn the motion at an arbitrary position and orientation.